code: def __init__(self, frontend_url=None, **kwargs):
      super().__init__(**kwargs)
      self.frontend_url = frontend_url
      if self.frontend_url:
          # frontend_url is provided, using frontend
          try:
              res = httpx.get(frontend_url)
              if res.status_code == 200:
                  httpx.PoolLimits(max_keepalive=1, max_connections=1)
                  self.cli = httpx.Client()
                  print(
                      "Attempt connecting to Cluster Serving frontend success"
                  )
              else:
                  invalidInputError(False, "connection error")
          except Exception as e:
              print(
                  "Connection error, please check your HTTP server. Error msg is ",
                  e,
              )
      else:
          self.output_queue = OutputQueue(**kwargs)
  
      # TODO: these params can be read from config in future
      self.input_threshold = 0.6
      self.interval_if_error = 1
  
imports: import redis
  import time
  from bigdl.serving.schema import *
  import httpx
  import json
  import uuid
  from bigdl.serving.log4Error import invalidInputError
label_desc: Use image node_id 1 to create a new InputQueue object from inherited base classes: API with example: obj = InputQueue(frontend_url)